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In any triangle, the square of the side opposite an acute angle is equal to the sum of the squares of the other two sides, minus twice the product of one of these sides and the projection of the other side upon it.
Yale University Entrance Examinations in Mathematics: 1884 to 1898 - Page 190
1898 - 208 pages

## The Elements of Geometry

Webster Wells - Geometry - 1894 - 256 pages
...THEOREM. 277. In any triangle, the square of the side opposite an acute angle is equal to the sum of the squares of the other two sides, minus twice the product of one of these sides and tlie projection of the other side upon it. Fig. 2. Let C be an acute angle of the triangle ABC, and...

## The Elements of Geometry

Webster Wells - Geometry - 1894 - 398 pages
...opposite an acute angle is equal to the sum of the squares of the other two sides, minus twice. tJie product of one of these sides and the projection of the other side upon it. D fig. 1. fig. 2. Let C be an acute angle of the triangle ABC, and draw AD perpendicular to CB, produced...

## An Examination Manual in Plane Geometry

George Albert Wentworth, George Anthony Hill - Geometry - 1894 - 150 pages
...opposite an acute angle is equivalent to the sum of the squares on the other two sides diminished by twice the product of one of these sides and the projection of the other upon that side. 4. Prove that regular polygons of the same number of sides are similar figures. SHEFFIELD...

## Elementary Synthetic Geometry of the Point, Line and Circle in the Plane

Nathan Fellowes Dupuis - Geometry - 1894 - 313 pages
...acute angle is less than the sum of the squares upon the other two sides by twice the rectangle on one of these sides and the projection of the other side upon it. 3. Let the angle A become obtuse. Then D, the foot of the altitude to by passes beyond A, and L\ changes...

## Plane and Spherical Trigonometry

Alfred Hix Welsh - Plane trigonometry - 1894 - 228 pages
...37. PROPERTIES OF TRIANGLES. THEOREM I. The square of any side of a triangle is equal to the sum of the squares of the other two sides, minus twice the product of these sides into the cosine of their included angle. If the included angle, as A, is acute, a2 = V1...

## Elements of Geometry

Andrew Wheeler Phillips, Irving Fisher - Geometry - 1896 - 554 pages
...THEOREM 325. In any triangle, the square of the side opposite an acute angle is equal to the sum of the squares of the other two sides, minus twice the...sides and the projection of the other side upon it. a no. t n FIG. • GIVEN the triangle ABC and C, an acute angle. Draw AD perpendicular to CB or CB...

## Elements of Geometry, Volume 1

Andrew Wheeler Phillips, Irving Fisher - Geometry, Modern - 1896 - 276 pages
...THEOREM 325. In any triangle, the square of the side opposite an acute angle is equal to the sum of the squares of the other two sides, minus twice the...sides and the projection of the other side upon it. a, FIG. i n FIG. a GIVEN the triangle ABC and C, an acute angle. Draw AD perpendicular to CB or CB...

## Elements of Geometry, Part 1

Andrew Wheeler Phillips, Irving Fisher - Geometry - 1896 - 276 pages
...the side opposite the obtuse angle is equal to the sum of the squares of the other two sides, plus twice the product of one of these sides and the projection of the other side upon it. GIVEN — the obtuse-angled triangle ABC with B the obtuse angle. Draw AD perpendicular to CB produced,...